TRANSMISSION OF CRYPTOCOTYLE-LINGUA CERCARIAE IN NATURAL ENVIRONMENTS- A FIELD EXPERIMENT

Atlantic cod were kept at two different depths in three cages placed a t increasing distance from a rocky shore where natural infections of t he digenean Cryptocotyle lingua occurred in the snail Littorina littor ea. During a 6-month period the fish kept at 0-2 m accumulated signifi cantly more parasites than those kept at 2-4 m. Distance from the shor e did not affect infection rates. We conclude that host location behav iour of cercariae influences the infection pattern under natural condi tions, and that transmission from snail to fish can take place over la rge areas of coastal waters. (C) 1998 The Fisheries Society of the Bri tish Isles.